Page:Evolution of the thermometer.djvu/60

ming that the excesses of the heats of the iron and of the solidified substances, above the heat of the atmosphere, were in geometrical progression when the times were in arithmetical progression, all the heats were obtained. From this experiment and computation Newton drew up the following scale of degrees of heat.

Newton's Table.

Degrees
of
heat.

Equal
parts of
heat.

Phenomena.

0

0

heat of the winter air when water begins to freeze.

1

12

greatest heat of the surface of the human body.

2

24

heat of melting wax.

2.5

34

heat of water boiling vehemently.

3

48

lowest heat at which equal parts of tin and bismuth melt.

4

96

lowest heat at which lead melts.

5

192

heat of a small coal fire not urged by bellows.

Biot, commenting on Newton's paper, notes that it contains three important discoveries: (1) a method of making thermometers comparable by determining the extreme terms of their graduation from the phenomena of constant temperature; (2) the determination of the law of cooling in solid bodies at moderate temperatures; (3) observation of the constancy of temperature in fusion and ebullition.